Haemophilus influenzae meningitis is a bacterial infection of the membranes covering the brain and spinal cord (meninges).
H. influenzae meningitis is caused by Haemophilus influenzae bacteria. This illness is not the same as the flu (influenza), which is caused by a virus.
Before the Hib vaccine, H. influenzae was the leading cause of bacterial meningitis in children under age 5. Since the vaccine became available in the United States, this type of meningitis occurs in less than 2 in 100,000 children.
H. influenzae meningitis may occur after an upper respiratory infection. The infection usually spreads from your lungs and airways to your blood, then the brain area.
Risk factors include:
Symptoms usually come on quickly, and may include:
- Fever and chills
- Mental status changes
- Nausea and vomiting
- Sensitivity to light (photophobia)
- Severe headache
- Stiff neck (meningismus)
Other symptoms that can occur include:
- Bulging fontanelles in infants
- Decreased consciousness
- Poor feeding and irritability in children
- Rapid breathing
- Unusual posture, with the head and neck arched backwards
Exams and Tests
The doctor or nurse will examine you. This will usually show:
- Fast heart rate
- Mental status changes
- Stiff neck
If the doctor thinks menigitis is possible, a lumbar puncture ("spinal tap") is done to take a sample of spinal fluid (cerebrospinal fluid, or CSF) for testing.
Other tests that may be done include:
Antibiotics should be given as soon as possible. Ceftriaxone is one of the most commonly used antibiotics. Ampicillin may sometimes be used.
Corticosteroids may be used to fight inflammation, especially in children.
Unvaccinated people who are in close contact with someone who has H. influenzae meningitis should be given antibiotics to prevent infection. Such people include:
- Household members
- Roommates in dormitories
- Those who come into close contact with an infected person
This is a dangerous infection and it can be deadly. The faster you are treated, the better your chance for recovery. Young children and adults over age 50 have the highest risk of death.
When to Contact a Medical Professional
Call the local emergency number (such as 911) or go to an emergency room if you suspect meningitis in a young child who has the following symptoms:
- Feeding problems
- High-pitched cry
- Persistent, unexplained fever
Call the local emergency number if you develop any of the serious symptoms listed above. Meningitis can quickly become a life-threatening illness.
To protect infants and young children:
- Hib immunizations for infants and children are recommended by the American Academy of Pediatrics and the Advisory Committee on Immunization Practices.
- Several types of Hib vaccine are available for children ages 2 months and older.
All unvaccinated family members and close contacts (especially in health care or school settings) of people with this type of meningitis should begin antibiotic treatment as soon as possible to prevent spread of the infection. Ask your health care provider about antibiotics during the first visit.
Close contacts in the same household, school, or day care center should be watched for early signs of the disease as soon as the first case is diagnosed. If two cases occur in a day care center, preventive antibiotics may be considered. Always use good hygiene habits, such as washing hands before and after changing a diaper, and after using the bathroom.
H. influenzae meningitis; H. flu meningitis
Prober CG, Dyner L. Central nervous system infections. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 595.
Swartz MN. Meningitis: bacterial, viral, and other. In: Goldman L, Ausiello D, eds. Goldman's Cecil Medicine. 23rd ed. Philadelphia, PA: Elsevier Saunders; 2007:chap 437.
Thigpen MC, Whitney CG, Messonnier NE, et al. Emerging Infections Programs Network. Bacterial meningitis in the United States, 1998-2007. N Engl J Med. 2011 May 26;364:2016-2025.
Update Date 8/31/2014
Updated by: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.